Fabrication of low defectivity electrochromic devices

Abstract

Prior electrochromic devices frequently suffer from high levels of defectivity. The defects may be manifest as pin holes or spots where the electrochromic transition is impaired. This is unacceptable for many applications such as electrochromic architectural glass. Improved electrochromic devices with low defectivity can be fabricated by depositing certain layered components of the electrochromic device in a single integrated deposition system. While these layers are being deposited and/or treated on a substrate, for example a glass window, the substrate never leaves a controlled ambient environment, for example a low pressure controlled atmosphere having very low levels of particles. These layers may be deposited using physical vapor deposition.

What is claimed is: 
     
       1. A method of fabricating an electrochromic device, the method comprising:
 a) depositing one or more metal oxide layers on a substrate, the one or more metal oxide layers comprising either an electrochromic material layer or an electrochromic material layer and a counter electrode material layer; and 
 b) depositing lithium metal onto the one or more metal oxide layers; wherein the substrate is in a substantially vertical orientation while the lithium metal is deposited on the one or more metal oxide layers. 
 
     
     
       2. The method of  claim 1 , wherein the lithium metal is deposited onto either or both of the electrochromic material layer and the counter electrode material layer. 
     
     
       3. The method of  claim 1 , wherein the electrochromic material layer comprises tungsten oxide. 
     
     
       4. The method of  claim 3 , wherein the counter electrode material layer comprises nickel oxide. 
     
     
       5. The method of  claim 3 , wherein the counter electrode material layer comprises nickel tungsten oxide. 
     
     
       6. The method of  claim 5 , wherein the nickel tungsten oxide is doped with tantalum. 
     
     
       7. The method of  claim 2 , wherein the ratio of thicknesses of the electrochromic material layer to the counter electrode material layer is between about 1.7:1 and 2.3:1. 
     
     
       8. The method of  claim 1 , wherein the counter electrode material layer comprises at least one metal oxide selected from the group consisting of tungsten oxide, molybdenum oxide, niobium oxide, titanium oxide, copper oxide, iridium oxide, chromium oxide, manganese oxide, vanadium oxide, nickel oxide, and cobalt oxide. 
     
     
       9. The method of  claim 1 , wherein depositing the one or more metal oxide layers on the substrate further comprises depositing an ion conductor layer between the electrochromic material layer and the counter electrode material layer. 
     
     
       10. The method of  claim 1 , wherein depositing the one or more metal oxide layers on the substrate comprises depositing the electrochromic material layer, an ion conducting layer, and the counter electrode material layer on the substrate, in that order. 
     
     
       11. The method of  claim 1 , wherein depositing the one or more metal oxide layers on the substrate comprises depositing the counter electrode material layer, an ion conducting layer, and the electrochromic material layer, on the substrate, in that order. 
     
     
       12. The method of  claim 1 , wherein the substrate is a glass substrate and comprises a first transparent conducting oxide layer deposited thereon, and wherein the one or more metal oxide layers of the electrochromic device are deposited on the first transparent conducting oxide layer. 
     
     
       13. The method of  claim 12 , further comprising depositing a second transparent conducting oxide layer on the one or more metal oxide layers after depositing lithium metal. 
     
     
       14. The method of  claim 13 , wherein the second transparent conducting layer comprises indium tin oxide. 
     
     
       15. The method of  claim 13 , wherein each of the first and second transparent conducting layers has a thickness between about 10 nm and about 1,000 nm. 
     
     
       16. The method of  claim 13 , wherein each of the first and second transparent conducting layers has a sheet resistance of about 5 to about 30 ohms per square. 
     
     
       17. The method of  claim 12 , wherein the glass substrate comprises a sodium diffusion barrier between the first transparent conducting oxide layer and the glass substrate. 
     
     
       18. The method of  claim 17 , wherein the glass substrate is soda lime float glass. 
     
     
       19. The method of  claim 18 , wherein the glass substrate is tempered. 
     
     
       20. The method of  claim 1 ,
 wherein depositing the one or more metal oxide layers comprises depositing an all solid state and inorganic electrochromic device stack; and 
 wherein the method further comprises tempering the all solid state and inorganic electrochromic device stack.